<!DOCTYPE html>
<html lang="zh">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>盒模型-圆角</title>
  <style>
    div {
      width: 640px;
      height: 160px;
      background-color: #f0f;
      /* 圆角 圆角半径 */
      /* border-radius: 20px; */
      /* border-radius: 10px 50px; */
      /* 胶囊形状 */
      border-radius: 80px;
    }
  </style>
</head>

<body>
  <div></div>
</body>

</html>